THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

MICHAEL HOLMES, CNN NARRATOR (voice-over): It began as a food drop and turned into a rescue mission.

IVAN WATSON, CNN SENIOR INTERNATIONAL CORRESPONDENT: This has been one chaotic aid distribution.

HOLMES: As CNN Correspondent Ivan Watson and his crew got their first glimpse of the Yazidi people stranded on Mt. Sinjar in northern Iraq, they suddenly found themselves witness to a scramble for survival.

WATSON: We made a second pass where we came down.

UNIDENTIFIED MALE: Here they come.

WATSON: They're just hurling themselves into the helicopter. At that point it was just insanity, just people piling in, screaming, running for their lives, to get on this helicopter. And they were -- they were frightened. They were horrified. And that was like a punch to the gut.

I can't describe to you how relieved people are right now. They're just shocked in the chaos of that moment. But we've got little Aziza here. She's not happy because she says her father got left behind.

I couldn't get my eyes off of Aziza, because she just looked so innocent and just this kind of picture of innocence. And shouldn't be in this position. It's just not right.

MARK PHILLIPS, PHOTOJOURNALIST: She had this face of panic and sheer horror. Those things will never leave you.

HOLMES: Aziza, frightened and confused. The little girl's tears begged for answers. How did she end up on the top of this mountain? Where was her family? And for the thousands of families trying to escape massacre, how had it come to this?

When Watson and his team set out to report on the plight of the Yazidi people in early August, the humanitarian disaster had been unfolding for months. More than half a million people displaced since June alone.

WATSON: We'd heard about Yazidis being trapped and on the run, but the people we were encountering were Iraqi Christians and they were Arab Shiites and members of other ethnic and religious groups. So the initial crisis that had prompted us to come to Iraqi Kurdistan was superseded by another one unfolding in front of us.

HOLMES: Iraq is being ripped apart by Islamic militants trying to set up an Islamic state. Known as ISIS, they're invading Iraq from the north, killing anyone in their path who doesn't comply with their severe brand of Islam.

The Yazidis are an ancient religious sect with its own set of beliefs about God. They fled to the mountains in northern Iraq, praying ISIS wouldn't follow.

GUL TUYSUZ, CNN PRODUCER: There was a piece of video that came out from on top of Sinjar mountain from the Farq news agency, and it was really, I think, the first sort of awakening we had. It was a bunch of kids on top of the mountain, and they were crying and wailing. And it was just a horrific video. And I think that really sort of set things in motion, that we need to get there. But it was logistically a difficult thing to do.

WATSON: We landed in a city that was very much on edge. And then I pieced together in the days that followed that the leadership of that city feared that it would fall that night. People were actually running for the mountains as we were picking up our suitcases and our equipment off of the luggage carousel.

HOLMES: All along the journey, signs of people fleeing for their lives.

WATSON: And it was an eerie sight to see just these rows of scores of tents there on this sun burnt plain, and they were all just empty. It's an eerie, eerie feeling to see that empty no-man's land, and to recognize that the people who triggered that exodus are only a couple miles away from where you're standing.

The response to the American air strikes was immediate relief, not only the Kurdish leaders who realized how vulnerable they had been, but also the fighters on the front lines got an immediate injection of morale boost and new confidence. And in the subsequent days, they actually went on the offensive and recaptured territory that they had lost just days before.

HOLMES: The CNN crew arrives in the town of Erbil and finds families camped out in a catholic church.

WATSON: Seeing these people sleeping in the pews, seeing these babies and children and elderly people in this house of worship because they had nowhere else to go was deeply emotional. And at one point there, I'm walking around. I'm trying to wrap my head around this thing, and I almost stepped on this baby sleeping on the floor. And it was the first time in this week of kind of human misery and a suffering that we've been documenting, that was the first time that I choked up and started crying.

I was personally very surprised to see these people just kind of showing up and walking into these unfinished buildings, these office buildings or apartment buildings and just starting to camp out there, not having any other place to go. No water, no food?

UNIDENTIFIED MALE: No water, no food, nothing.

WATSON: Nothing.

UNIDENTIFIED MALE: Nothing anything.

WATSON: And it just I think illustrates how overwhelming these scenes of people on the run have been.

UNIDENTIFIED FEMALE: What we do? What we do now? We want solution to this problem, please.

HOLMES: And beyond the towns and the makeshift shelters, there are thousands more still stranded on Mt. Sinjar.

WATSON: We were hearing that there were aid drops taking place.

TUYSUZ: We had to get on that helicopter. Our crew had to get on that helicopter.

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HOLMES (voice-over): For days CNN correspondent Ivan Watson and his team had been hearing about a humanitarian crisis unfolding on a mountaintop in northern Iraq near the city of Sinjar. When ISIS moved in, the civilians moved out and up to Sinjar mountain. Little water, even less food. It was a crisis the team needed to see for themselves.

WATSON: I'd been offered two ways to try to go see the Yazidis trapped on Mt. Sinjar. One was to cross the border into Syria and come back into Iraq and then hike for miles to Mt. Sinjar and then hike up the mountain. The other was to perhaps try to get some kind of a helicopter to the mountain. We were hearing that there were aid drops taking place.

TUYSUZ: It was sort of the only way to get on top of this Masada like mountaintop that the Yazidis were in. And, you know, it was surrounded by ISIS.

HOLMES: After days of waiting, the CNN team was granted permission to accompany a mixed crew of Kurdish Peshmerga and Iraqi air force personnel on an aid drop mission to Mt. Sinjar.

WATSON: I knew that this was a dangerous trip. But I thought that going to see what was taking place was worth that risk. Fifteen minutes into the flight, they are just unloading their machine guns. And they're picking out targets down below. And we can't see what is going on. We can't communicate with them. We don't have the headphones. But they're really going through ammunition. And their shell cases raining out of these machine guns and landing on the helicopter floor. And the gunners are kicking the shell casings off the aircraft, and they're tumbling down into space. And I realize that these guys are scared. These guys are frightened. They're laying down suppressing fire. And for all I know, somebody is shooting at us. We can't tell. So that started to really freak me out.

They're opening fire at targets down below. They say they regularly exchange fire on these trips. And they're clearly trying to defend the aircraft.

They'd been shooting for a while, and then I could see in the distance through the big gunner door, and knew immediately that that is Mt. Sinjar. And as we moved further in and started circling over, for the first time I spotted humans on the mountain. And we knew that we were definitely here, and we were getting our eyes on these people for the first time. And get a glimpse of what they had been going through.

You can see the people below trapped on Sinjar mountain. They're clustered under olive trees right now, waving to us. A lot of women and children waving.

I couldn't believe my eyes. One of the gunners kicked this bag of food out the door. And we were at least -- at least 60 feet up. It was insane.

This has been one chaotic aid distribution. I mean, I really hope we didn't hurt anybody with the bottles of water we were throwing down from a height of 20, 30 feet.

Finally, the helicopter touch down for a minute.

Here they come.

They surged in, and they began piling into the helicopter. The people we were with, the crew and the Peshmerga, didn't have a plan in mind for how they were going to handle this. And it was just madness. At that point, it was just insanity. Just people piling in, screaming, running for their lives to get on this helicopter.

PHILLIPS: I was trying to get in position where I could shoot them without actually being knocked down by them. The helicopter was moving around. So you're trying to hold on to something. I could see Ivan in front of me helping people on. But my job was to make sure I could record what was happening.

WATSON: They were frightened. They were horrified. And that was like a punch to the gut, because here you are trying to get people in, and trying to be happy for them. We're going to try to get you out of here. But they're terrified and they're weeping and they're screaming.

Then there was this beautiful little girl right in the middle of this who was just crying and crying and weeping and weeping.

We've got little Aziza here. She's not happy. She says her father got left behind.

How do you comfort a child that's been through this ordeal? And there's a machine gun blasting away next to you. And god knows we could get hit by incoming fire. I don't know.

PHILLIPS: I'm here to give people a voice. If I can't give them a voice, then who will?

You empathize with them very much. You know, what would I do if I were in their position? How would I continue on? And I think for Ivan, I could see him looking at that going, what if that was me? What if that was my family, how would I cope with that?

We landed, and that -- that was a tremendous relief. And the people started coming out of the helicopter. I went up and I talked to Aziza's older brother, and I kind of spoke a little bit more and I exchanged phone numbers with him. And they were getting loaded up onto a bus when I said goodbye. I said, we're going to stay in touch. All of us felt so drained by the ordeal. Everybody in our team has been around the block a few times. But none of us had experienced anything quite like this before.

TUYSUZ: Getting off that flight, the guys knew that this was a family that they immediately cared for deeply. It wasn't a decision made on any intellectual level. It was just like, well, we're going to go and we're going to follow the girl in the purple.

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HOLMES (voice-over): It is perhaps hard to fathom, but Aziza and her family were the lucky ones. Scores of other Yazidis were forced to flee ISIS by foot, a brutal journey some would not survive.

TUYSUZ: This unbelievable sight at the Peshka River crossing between Syria and Iraq where just hundreds of people were streaming across this dingy little bridge.

WATSON: It was this kind of silent kind of procession of very sad and very tired people.

We've been watching a stream of desperate families carrying little more than the clothes on their backs walking, some of these people --

I was about to do a live report with a crowd shuffling past. And some reunion happened there, some young, thin man with a beard I think saw his family.

Oh, this is beautiful.

They'd clearly been separated. He was there waiting for them. And he just started weeping and embracing them and hugging them.

I don't know. I just kind of kept crying over and over again.

Those people coming across were people who had just experienced all of that. And some of them had left their babies behind because they couldn't carry them anymore, or because their babies had just died in the desert on the march.

There was one family we met that they didn't go 50 feet beyond the end of the bridge. They just -- this is where we're sleeping tonight. A Kurdish security guard tried to move them. They were not going to move. That was where they were going to sleep that night. And everybody else was just homeless and going to find some patch of, if they were lucky, grass to sleep on tonight somewhere here in Iraqi Kurdistan. They're safe, but they're refugees now.

Can we see?

HOLMES: In the midst of such suffering, Ivan and the team make it their mission to find Aziza's family.

TUYSUZ: I don't think it was ever a question of whether or not we'd go and find Aziza. I think it was just a matter of when do we do it.

WATSON: Sure enough there is this giant derelict building. The family is just clustered up against this wall. And I walk up and then I see this little kid with this ridiculous red hair, this carrot-top sitting there. It was the same baby I held. I remember you. Hi! Aziza. Hi, it's good to see you.

And nobody is crying finally. It's a normal chance to get to know each other for a couple of hours. And it's wonderful. And we get to hear the family's whole story. But early on I ask about their father. First of all, he is one stubborn old man, because when ISIS was rolling into Sinjar and every Yazidi in the town is packing up their cars and running, his oldest son says, my dad refused to leave, he said it would be a humiliation. If they kill me, let me die here, I'm going to stay in my house. And that family, can you imagine the gut- wrenching decision they must have had to make, to leave their dad behind.

UNIDENTIFIED MALE (through translator): we all tried hard to convince my dad but he refused to go. He said it would be a humiliation. I decided I couldn't let them capture the girls and women, so we left.

WATSON: But a day after they landed in safety here in Iraqi Kurdistan, the oldest son gets a phone call. And it's a fighter from the Kurdistan workers party, PKK. And he passes the phone to his father, and his father is alive. The PKK fighters came into Sinjar and rescued that stubborn man from the house that he had been trapped in and brought him up the mountain. And the latest news that the family got was that the father was up there on that mountain.

The kids are smiling. They're -- it's -- they're delighted. What are they going to do with dad? Fabid (ph), the oldest son, he said, dad, don't do the walk of death. Don't walk to Syria. Stay there and you'll get a flight out. That's our plan. So that's the plan. And I said, how's the dad doing, how is he? Is he OK? They said -- they said he's strong, he can survive up there. There's food and water that's been delivered by the aid flights. He can survive up there. Until he gets reunited with the family.

You ask the kids, what do you want most right now, and Dunia (ph), who turned into this 17-year-old chatterbox, said my dream is to see my dad again. Once he gets here, everything is going to be OK.

PHILLIPS: When we walked way, you did consider what future they had, you know, what was the next step, what was tomorrow going to bring. And you wish them all the best.

WATSON: There's a family sleeping in the mud there. They had a house a week ago. That's insane. And it's not a natural disaster that caused that. That's other human beings made that and are responsible for that. I fell to pieces and I know that some of the other guys on the team did too. It was just -- it doesn't get easier. It just gets worse, because you know that these people are going to have a terrible probably, not just a couple of months, but couple of years. And you know that that's what in store for them and it just -- it is just so awful.